1. Field of the Invention
This invention relates to a closed loop dispensing system and more particularly to a dispensing system for dispensing corrosive liquid chemical or dangerous medical liquid products which are typically drawn from a container, such as a bottle or the like. Even more particularly, this invention relates to a container insert or throat plug which is press-fitted into the throat of the container with the container insert including a venting membrane for relieving vacuum pressure from within the bottle. Even more particularly, this invention relates to a means for preventing damage to the venting membrane when the retaining disc of the container insert is threadably secured to the lower end thereof
2. Description of the Related Art
Many container inserts have been previously provided wherein a venting membrane is held in place in the container insert by a disc which is threadably secured to the lower end of the container insert. See for example, Applicant's U.S. Pat. Nos. 6,968,983; 6,669,062; 6,142,345 and 5,988,456. The venting membranes of the prior art are disc-shaped and are quite fragile. In some cases, when the retainer disc is threadably secured to the lower end of the container insert, the fragile venting membrane is torn or otherwise damaged due to the rotation of the retaining disc with respect to the venting membrane.